Coma

Being in a coma means you’re unconscious, unaware and unresponsive to what’s happening around you. It also blocks your awareness of yourself, including your body’s status and anything your body needs. At the most basic level, a coma means your brain isn’t working as it should.

Comas are a possible complication of conditions that can severely disrupt or damage your brain. A coma is different from person to person. Comas have levels of severity, and some are deeper — meaning the severity of brain activity disruption is greater — than others.

A coma is a medical emergency. If you’re with someone who’s unconscious and unresponsive, call 911 (or your local emergency services number) immediately. Many causes of coma need immediate medical care, and any delay could lead to dangerous complications or death.

How common are comas?

The available research suggests that there are a little over 250 new comas per 100,000 people in the population of the United States and the United Kingdom each year. However, there’s uncertainty about the accuracy of that estimate. And there are multiple reasons for that uncertainty. One major reason is that some common causes of coma are treatable and quickly reversible by first responders, sometimes without the need for a hospital visit. Another reason is that many conditions look like comas but are actually something else.

Comas can affect anyone who has a medical condition that affects the way their brain functions. They can happen to people regardless of age, sex, race, ethnicity or other demographic factors.